Micrometer caliper



March 8, 1960 J. R. OETTL MICROMETER CALIPER 2 Sheets-Sheet 1 Filed Sept. 8, 1958 March 8, 1960 J. R. O ETTL 2,927,376

MICROMETER CALIPER Filed Sept. 8, 1958 v 2 Sheets-Sheet 2 JOHN R OETTL BY c M g? MICROMETER CALIPER John Robert Oettl, Hollis, N.Y. Application September s, 1958, Serial No. 7ss,747

Claims. (Cl. 33-147) The present invention relates to micrometer calipers and more particularly to a micrometer caliper having a movable spindle biased into engagement with the anvil and retractable therefrom by means of a finger actuatable lever.

It is an object of the present invention to provide a micrometer caliper for making very exact measurements, but which does not employ a fine threaded worm gear.

It is another object of the present invention to provide a micrometer caliper employing two rack gears attached to and directed oppositely toone another for engaging two gears secured to indicatingdials, the latter gears being mounted for rotation about a common center and being rotated in opposite directions by the two rack gears.

It is another object of the present invention to provide a relatively simple and inexpensive micrometer caliper which provides for very exact measurement of bodies placed between a caliper spindle and caliper anvil.

It is yet another object of the present invention to provide a micrometer caliper having a spindle spring-biased into engagement with an anvil and employing a finger actuatable lever for controlling movement of the spindle toward and away from the anvil.

The above and still further objects, features and advantages of the present invention will become apparent upon consideration of the following detailed description of one specific embodiment thereof, especially'when taken in conjunction with the accompanying drawings, wherein:

Figure 1 is a perspective view of the micrometer caliper of the present invention;

Figure 2 is an exploded view illustrating the various parts of the micrometer caliper of the present invention;

Figure 3 is a top view of the micrometer caliper of the present invention illustrating the various measuring dials and wheels;

Figure 4 is a vertical cross-sectional view taken along section 4-4 of Figure 3; and

Figure 5 is a vertical cross-sectional view taken along section 55 of Figure 3, of the accompanying drawings.

Referring now to Figures 1 through 3 of the accompanying drawings, there is provided a generally U-shaped' frame member 1 terminating in an anvil 2 adapted to be engaged by a longitudinally reciprocatable spindle 3. Movement of the spindle 3 is controlled by a rotatable lever 4 which may be engaged by the finger of the user. The spindle 3 is reciprocatable within a channel-shaped body member 6 having an indicating dial 7 disposed on the upper surface thereof.

Referring now specifically to Figures 2, 4 and 5, the spindle 3 forms the end portion of a generally rectangular bar 8 disposed against a bottom wall 9 of the channelshaped member 6. The central portion of the bar 8 is provided with a rectangular recess 11 formed in the surface of the body 6 remote from the bottom wall 9 of the channel-shaped body 6. The recess 11 provides a section 12 of the bar 8 of reduced width which is provided with a further recess 13 in the bottom surface thereof, as viewed in Figure 2. The recess 13 is substantially nitcd States Patent 0 2,927,376 Patented Mar. 8, 1960 ice coextensive with the recess 11. A rack gear 14 is secured to the section 12 and disposed wholly within the recess 13 so far as vertical height, as viewed in Figure 2, is concerned. The rack gear 14 is provided with a pinrality of teeth 16 extending outwardly into the recess '11. The teeth 16 are adapted to be engaged by gear teeth 17 formed along the lower extremity of a shaft 18 which terminates at its upper extremity in a circular disc 19. The disc 19 is suitably bolted to a flat, circular indicator dial 21.

The shaft 18 and dial 21 are supported by a first ball bearing arrangement 22 supported centrally of a further indicator dial 23. The dial 23 has a recess in its upper surface to receive the dial 21 and has a central aperture 24 through which the shaft 18 extends and in which the ball bearing 22 is supported. The dial 23 is supported on ball bearings 26 which are supported in a centrally disposed circular aperture 27 formed in a hub 33 which depends downwardly from a stationary dial 255. The dial 28 has a vertically extending circumferential flange 29 defining a depressed region 31 in which the disc 19, dial 21 and dial 23 are disposed. A glass cover 32 is secured within the circular flange 29 and covers the dial faces so as to prevent them from becoming soiled. The hub 33 is disposed in a circular aperture 34 formed inthe upper roll, as viewed in Figure 2, of the channelshaped body 6. The stationary dial 28 may be secured to the upper wall of the body 6 as by bolting or by other suitable means.

The shaft 18 on which the gear teeth 17 are formed extends downwardly below the rack 14 and into engagement with a circular gear 36 having an axle 37. The gear 36 is disposed in a recess 38 formed in the bottom wall, as viewed in Figures 2, 4 and 5, of the channelshaped member 6, which recess is symmetrical with respect to the axis of the aperture 34 in the upper wall of the channel-shaped body. The recess 38 is covered by a plate 39 and the axle 37 of the circular gear 36 extends into apertures in the bottom wall of the body 6 and the upper wall of the plate 39 as viewed in Figure 5. A spiral spring 41 has its inner convolution secured to the axle 37 and its outer convolution secured to the body 6. The spring 41 is arranged so that it tends to rotate the shaft 18 in a direction to move the rack gear 14, the attached bar 8 and the spindle 3 toward and into engagement with the anvil 2.

Considering for the moment, only those elements thus far described, movement of the spindle 3 produces movement of the rack gear 14 and rotation of the shaft 18. Rotation of the shaft 18 is transmitted to the disc 19 and dial 21 which registers movement of the spindle relative to the anvil. The number of teeth of the rack gear 14 and the shaft 18 determines the number of degrees of rotation of the dial 21 for each incremental movement of the spindle.

A rectangular bar 42 is secured to the surface of the bar 8 bearing the recess 11 and is provided in the region of the recess 11 with gear teeth 43 so that the bar 42 constitutes a further rack gear. The upper surface of the bar 42 is provided with a recess 44 which is adapted to accommodate a portion of the lever 4 as will become apparent subsequently. The dial 23 is provided with a downwardly depending cylindrical hollow member 46 disposed about the shaft 18 and within the hub 33 of the stationary dial 28. The outer circumferential surface of the cylinder 46 is provided with axially extending gear teeth 47 which engage the gear teeth 43 on the bar 42 and, therefore, as the bar 8 and the bar 42 reciprocate, the cylinder 46, and in consequence the dial 23, are rotated. It will be noted that the dial 23 rotates in an opposite direction from the dial 21 since the bars 8 and 42 are moving in the same direction, but the teeth which.

engage the shaft 18 and cylinder 46 are disposed on diametrically opposed sides of these latter two members.

The members thus far described may be suitably secured in the channel shapedbod-y 6 as by punch pins or bolts and are further retained therein by a rectangular longitudinal extension 48 of the U-shaped frame member 1. The extension 48 extends perpendicular to the legs of the U-shaped member 1 and is disposed between the side walls ofthe channeled body 6, forwardly, as viewed in- Figure 2, or the combined bars 8 and 42. The rectangular extension 48 may be suitably secured between the side walls of the channel member 6 and is provided' with a recess 49 in its upper surface as viewed in Figure 2, to accept the lever 4. The lever 4 comprises a generally wedge shaped'body 51 which is disposed between the upper side wall ofthe channel shaped body 6 and the extension 48 and terminates outwardly thereof in a skirt member 52 which is adapted to be engaged by the finger of the user. The wedge shaped body, approximately midway between its ends, is provided with an aperture 53 which receives an axle or a shaft 54 fixedly secured in the middle of the recess 49 in the rectangular extension 48 of the U-shaped member 1. Secured to the bottom of the Wedge shaped body 51 is the inner convolution of a spiral spring 56 havingits outer convolution secured to the extension 48. The arcuate portion of the wedge shaped body 51 is provided with gear teeth 57 which extend into engagement with the gear teeth 47 formed on the outer surface of the cylinder 46. Thus as theleverd is rotated about the shaft 54, the cylinder'46 is rotated producing movement of the bars 8 and 42 and, therefore, also producing rotation of shaft 18 and of the dial 21, and further effecting withdrawal of the spindle 3 from the anvil 2. The spring 56 provides the main motivating force for urging the spindle 3 toward the anvil 2 while the spring 41, which urges the components in the same direction as the spring 56, is Weaker than the spring 56 and is employed primarily to eliminate backlash on the gear 36.

Reference is now made to the divisions, of the various dials of the apparatus and to a specific embodiment of the invention in which one complete rotation of the dial 23 with respect to the dial 28 represents a movement of the spindle 3 from the anvil 2 by one half of an inch. The dial 28 has 50 equally spaced radial lines 58 about its periphery and, therefore, a movement of the zero. line 59 on the dial 23 from one of the lines 58 to the next line represents a movement of spindle 3 of 0.01 inch. The dial, 21 is employed as a vernier and is provided with 9 equally spaced radial lines 60 about its periphery. Initially one of the lines 60 is lined up with the zero lines on dial 28 and dial 23; As the dial 21 is rotated clockwise, as viewed in Figure 3, the line 60 initially adjacent the line 1 on dial 23 lines up with the line 1 and indicates a movement of the spindle of 0.001 inch. Continued rotation of the dial 21 brings each succeeding one of'the 9 lines 60 into registry with the lines 59 marked 2-9 respectively. When the line 60, which was initially adjacent the line 1 on dial 23, coincides with the first line 59 counterclockwise of the line 59 marked 0, the spindle 3 has moved 0.01 inch. If this process is repeated nine times, the zero line on dial 23 is at 0.090 on the dial 28. Also, the line 69 that was originally opposite the zero line. 59 on dial 23 is also opposite the 90 on dial 28. Therefore, the dial 21 has turned 0.82 turn for 0.09 turn on the dial 23. 'This ratio of movement determines the relative number of teeth on the rack gears and in a specific example of the apparatus, the bar 42 has 40 teeth per inch and the corresponding rack gear must have 20 teeth per inch; and rack gear 14has 72.888

anemi will be understood that the non-rotating spindle. is suitable tor a number of adaptors to take measurements, which would not be possible on the usual or standard micrometer. In addition, the constant pressure applied by spiral spring 56 provides for very accurate measurements as compared to the usual micrometers which must depend on the skill of the operators hand pressure.

If desired, the dial numbers and dial lines of the dial members 21 and 23 may be oppositely colored for ease in reading. For instance, the. numbers and lines of the large dial 28 may be red and the numbers and lines of the smaller dial 21 or- 23 may be green.

While I have described and illustrated one specific embodiment of my invention, it will be clear that variations of the details of construction which are specifically illustrated and described may be resorted to without departing from the true spirit and'scope of the invention as defined in the appended claims.

What I claim is l. A micrometer caliper comprising a first rack gear, a second rack gear, a spindle secured to one end of one of said rack gears, a body. element, said rack gears being secured together with their teeth facingone another and spaced from one another, said rack gears being slidably supported in said body element for reciprocating movement, an anvil secured to said body element and disposed in the path of movement of said spindle, a rotatable'shaft having external, axial gear teeth, said teeth of, said shaft engaging the teeth of-one of said rackgears, a rotatable hollow cylinder disposed; about said shaft and having external axially extending teeth engaging the other 'Of' said rack gears and a pair of dial indicators, said shaft and said hollow cylinder each'having a different one of said indicators secured thereto adjacent one another.

2. A micrometer caliper comprising a, first rack gear,

. a second rack gear, a spindle secured to one end of one of said rack gears, a. body element, saidrack gears being secured together withtheir teeth facing one another and spaced from one another, said rack gears being slidably supported in said body element for reciprocating movement, an anvil secured tosaid body element and disposed f h pa i movement of. said. a n li r atable s a t ha in ext rna axi y e e ding. gear e h. a d teeth o said. s aft engag ng, he eeth offqne o e d' ac g a a rotatable q w. sil nsie isposed bout a d haft an having external axially extendingteeth engaging the other of s i a e rs, aiur het s ar. h ying ge teeth orm on o nd. h r of. and fing r e aascabl Po i n i posed o ar ly at s d dna. s ftr r a ably pr ti g d further ge r o rot i n abou an. ax s para lel to the axis of rotation of said rotatable shaft, said gear teeth on said further gear engaging said gear teeth on said hollow cylinder.

3. A micrometer caliper. cOmp i ing a first rack gear, a s cond rackss r. a p nd se ured. to o e, d o n of said rack; gears, abody element, said, rack, gearsv being secured; together with their teeth facing one another and teeth per inch and the corresponding shaft 18 has 8 teeth.

spaced. from, one another, said rack gears being slidably supported in said body element for reciprocating movement, an anvil secured. to. said body' element and disposed in the path of movernent of said spindle, a rotatable shafthaving, external axial gear teeth, said teeth of said shaft engaging the teeth of one of said rack gears, a rotatable hollo'w cylinder. disposed about said shaftand having; external, axially extending teeth engaging therother; of, saidrack; gears, a further gear having gear; teeth engaging. said; gear; teeth on said rotatable shaft, and; a spring secured to and biasing said further gear for rotation in such; a direction as to, bring. said spindle; into engagement with said. anvil.

4. A micrometer calipercomprising a first rack gear, asecond rack gear-,a spindle secured to one end of one of.saidrackgears abody element, said rack gears being secured; together, wtih their; teeth facing. one. another and spaced from one another, said rack gears being slidably supported in said body element for reciprocating movement, an anvil secured to said body element and disposed in the path of movement of said spindle, a rotatable shaft having external axial gear teeth, said teeth of said shaft engaging the teeth of one of said rack gears, a rotatable hollow cylinder disposed about said shaft and having external aially extending teeth engaging the other of said rack gears, a first further gear having gear teeth formed on one end thereof and a finger engageable portion disposed outwardly of said body, a shaft for rotatably supporting said first further gear for rotation about an axis parallel to the axis of rotation of said rotatable shaft, said gear teeth on said first further gear engaging said gear teeth on said hollow cylinder, a second further gear having gear teeth engaging said gear teeth on said rotatable shaft, and a spring secured to and biasing said second further gear for rotation in such a direction as to bring said spindle into engagement with said anvil.

5. The combination according to claim 4 comprising a spring secured to and biasing said first further gear for rotation in a direction to bring said spindle into engagement with said anvil.

References Cited in the file of this patent UNITED STATES PATENTS 

